<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
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  <title>Document</title>
  <style>
    /* 视口宽度小于等于768px，网页背景色为粉色 */
    @media (max-width: 768px) {
      body {
        background-color: pink;
      }
    }
    /* 视口宽度大于等于1200px，网页背景色为天蓝色 */
    @media (min-width: 1200px) {
      body {
        background-color: skyblue;
      }
    }
  </style>
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<body>
  
</body>
</html>